After a few days of using Feedlounge, my brief thoughts are thus.

The interface is very slick, the nicest of all the online feedreaders that I’ve seen so far.
Navigating around the feeds is very easy – always a good thing. The different view formats help a lot.
I love the ability to flag posts that I want to return to later.
Bugs – there have been a few, but nothing that makes it unuseable and they seem to be getting dealt with swiftly.

But is it worth $5 a month? For me, not really. There are plenty of other more practical things I could spend that money on. Personally I don’t think I can justify that cost simply to read news feeds, when I can do the same thing with almost the same ease with Blogbridge. But that’s just my personal choice, I’m sure there are plenty of others out there willing to pay.